Everyone has their own suggestions as to what good parts are for any set-up as well as performance mods.
I will offer some thoughts but would only encourage you to listen to what everyone has to say.

As for the parts you listed:
- Magic Box CNC Aluminum Performance Cylinder Head for Version 2 ( Double O-ring )
No.
- Magic Box Ultra Seal Ball Bearing Aluminum Piston Head ( Double O-Ring ),
No.This really depends on price for you can get the same quality for much cheaper but not double O-ring.
I am personally not "sold" on the idea that a Double O-ring is any better. Also consider the weight of the Piston Head given ROF goals you may have.
- Magic Box Ultra Efficient Teflon Coated Aluminum Cylinder For M16,
Maybe. Full Cylinder is the way to go IMO, but I personally do not like ribbed cylinder bodies.
- Sorbo.
Yes. You will need to AOE correct the piston other wise you will strip out Piston teeth 1-4.
- R-hop.
Yes, but......
Consider what distance you will actually be shooting at.
If you never shoot farther than 300' / 100 yards, then a Flat-hop will give you the same shooting performance as the R-hop, in my experience. If you plan on shooting past 300', then I would in fact advise going with R-hop. Either way, a FireFly Buffer Rubber / Namzu will work with both Flat-hop and R-hop as your Pressure Nub.
- Piston.
I would advise changing out the Piston.
A lot of guys here have their Piston's of choice.
Consider: Azimuth, Bravo Blue, SHS 15 tooth, System Supercore, and ASGI PE POM Polycarb Piston as well as other good ones that are out there,
- Motor.
Are there better motors than the stock KWA motor? Sure.
My advice would be to stay with the stock KWA motor and use a in-spec 11.1v Li-po to increase your trigger response. I have put my KWA motors through years of stress tests and am pretty impressed with the results. Save the purchase of a better motor until after you see what your stock KWA motor can really do.
- Inner Barrel.
The best performance you are going to get with your stock KWA Cylinder or an after-market Full Cylinder is with a 455mm inner barrel. Bore size is not as important as barrel quality. The inner barrel length does need to match your Cylinder and will do so more with a 455mm inner barrel than a 500+ mm inner barrel. I know you already spent the money on the KM barrel so use it, but buy a 455mm for comparison.
- bb's.
KWA .30's, yes.
Definitely give .32's and .36's a try.
The higher the weight, the better the accuracy and distance,
Use the heaviest ammo your gun will shoot for the specific distance you are shooting.
- Main Spring.
If you want 450fps, consider a KWA m130 spring.
Some get much higher fps with it than 450, but it has always been right at or around 450fps for me.
Just keep in mind the field rules where you play at for Full-Auto guns that shoot over 400fps.

General advice:
- Consider the cost of achieving performance.
If you spend enough time in airsoft and working on airsoft guns, you realize that you do not have to spend all your money to have the "best" performance. I can make a $200 gun build shoot just as far and accurate as a $400.00 gun build.
Motors, Inner Barrels, Mosfets, and varios stock gearbox internals are areas where you can not spend the money and get the same shooting performance. Is it better to have the best of these parts, yes. Is it necessary for the same performance for 100,000 rounds, No!
- True DMR.
A true DMR is Semi-Only.
This specifically means that your gun is in no way capable of shooting Full-Auto.
If you have Full-Auto capability, then what you have is a long range assault rifle, not a DMR.
DMR's are typically allowed a higher FPS than assualt rifles. So, if you build your gun to be a true DMR, go for the highest FPS allowed at the fields you airsoft at, Generally, DMR's are capped at 500fps measured in FPS using .20's.
- Build towards your performance goal, don't chase it.
Be smart. Don't "take the bate" that you have to have the latest and greatest of every part to be the best shooter. You just don't have to do that.

Summary:
This is what will make you a great shooting DMR:
1. Full Cylinder / Type-O.
2. 455mm quality inner barrel.
3. M120 Main Spring minimum, but go as high as field DMR limits will allow. (This helps with the heavier bb's more than anything).
4. Barrel Stabilization. (Vibration Control).
5. Barrel Lock-Down.
6. Quality heavy ammo.
7. Quality Piston
8. Quality shim job.
9. Flat-Hop, R-hop, or simply a quality Drop-in Bucking.
Yes. You read that right. A quality Drop-in Bucking will surprise you how well it can perform.
I bet I can out shoot a lot of R-hopped and Flat-hopped guns in the same class with my DMR using a Lonex 70 Degree Drop-in Bucking.
10. Shooting Skill.
Actual shooting skill is as important as any part or mod you can add to your gun.
Take the time and go to the range and simply learn the mechanincs of proper shooting technique.

@Gcw360 how did you tweak your nub with wire...can you elaborate sounds interesting

Sure, basically you find a wire that will fit into the hole of the nub to help to make the nub firmer and avoid collapsing when pressure is applied. I used a small insulated wire but you can use the copper core of any wire of appropriate gauge. Once you have found a wire of appropriate thickness you need to cut the lenght to match the nub's length. Then insert the wire into the nub and reinstall the nub in the hop-up. Here's a video that shows the same idea. The part they are using in the video would work too.....I just don't feel like paying $1.00 plus shipping for something I can make for nothing.

Ok thanks now to find some wire and test....this seems simple enough thanks for the reply

I just testest the reinforced nub ,and with it i was able to hit my target 180 feet away accurately and about 200 with a small burst
i was using Golden ball .25 and my kwa rifle with a DBC 300mm 6.01 TBB

Interests:Keeping those damn squirrels from putting their filthy little paws on my peaches in my backyard. Oh, Yes. It's not just a hobby, its a passion!!

Country:

Posted 17 July 2013 - 08:32 AM

biggy513, on 08 July 2013 - 10:46 AM, said:

@niko_gpsy would you recommend any other aftermarket nubs

I am a big fan of firefly buffer rubbers and have had really good results. But because they are on the expensive side I started making my own flat nubs with some material that wgusler sent me. Works really great with any type of bucking and FPS.

Any suggestions are greatly appreciated. I am aiming for 450 fps (field limit for a DMR), a fluctuation of 3-5 fps per shot, and I will be shooting in semi auto only. What spring should I get m130 or m120? Which brand of inner barrels are best? I am trying to get one in the 450mm range as suggested by vanevery. Thanks for your time and cooperation!

· Lonex Blue Polycarbonate Piston for Version 2 (Does the red one fit, supposedly it is stronger and more reinforced.)

· Lonex Version 2 Cylinder Head

· Lonex Full Steel Cylinder

· Lonex 70 Degree Hard Bucking

· Lonex Aluminum or POM Ventilation Piston Head (Which one Aluminum or POM?)

· ProWin M4/M16 CNC Hop Up Chamber (I have heard that this might not fit in gun, if so I will get the Lonex Metal Hop Up Chamber)

· Hunterseeker Armory IR Hop Z Kit

· Firefly - Namazu Flat Hop Nub with Roller Bar

· Sorbothane Pad (What thickness and hardness?)

· Hop-Up Unit O-Rings (They will be used for barrel stabilization and do they even fit?)

450 fps:
- It can be difficult to nail down a specific fps.
A lot of factors affect fps so a list of specific parts and mods may or may not get you there.
Could be more, could be less.
- As far as Main Spring goes, my KWA m130 spring purchased from the Pro Shop always netted me 450fps measured using .20's, give or take. Others on this forum state getting higher fps baseline readings with the same spring.
- The barrel length you use can affect that as well.
A 455mm will be better for performance, but may put you over the fps limit given whatever Main Spring you use vs using a 509mm.

Parts:
- Lonex Blue.
Yes.
Great Piston.
I have two of them.
Highly recommend them.

- Lonex Red.
Some production runs seem to not fit the KWA Sector Gear teeth.
Others say they use this piston in their KWA gun.

- Lonex Version 2 Cylinder head:
Maybe, maybe not.
You will have to try and see.
If you use it, you may need to stick with the KWA Air Nozzle.
KWA Cylinder Heads have worked best in my KWA guns, to date.

- Lonex Full Cylinder:
Yes.

Lonex 70 Degree Hard Bucking.
Yes. Absolutely!
You will need some 100% silicone oil applied to the bucking and Hop-up tube.
Hobby Shops sell it. It is known as Shock Oil. Get something around 30wt.
This is what I use:

Lonex Piston Head: Aluminum / POM
I say go with the Aluminum for I have used the Bravo version of this Piston Head in my DMR for a long time and get great results with it. Either one is fine.

IR-Hop / Z-kit.
Yes.
Good idea to have an extra Hop-up unit and barrel.
One for Modding and one for using Drop-in Buckings.
This way you always have a gun that works, even if your Hop-up mods don't for some reason.

Firefly Buffer Rubber / Namzu:
Yes.

Sorbo Pad:
Yes, but will require addressing the piston teeth 2-4 and will then give you AOE Correction provided the Sorbo pad is the right thickness. Usually a 1/8 thickness does the trick.

Hop-up Unit O -rings / Barrel Stabilization.
No.
Will not work well in your KWA gun.
I have a mod for this and a write up complete.
I just have not posted it on this forum yet.
I can PM you the link if you wish.